This invention relates to outlets for covered hopper railway cars and, more particularly, to an improved pneumatic outlet for such cars.
Pneumatic outlets for offloading lading from railcars such as covered hopper railway cars are well known in the art. See, for example, U.S. Pat. Nos. 4,382,725, 4,114,785, 3,778,114, 3,701,460, and 3,350,141, all of which are assigned to the same assignee as the present invention. An outlet of the type described in these patents includes a bottom cover extrusion which extends across the car from one side to the other. The extrusion is attached to respective side sheets and end sheets to complete the outlet body. A pair of outlet valves are housed within the bottom cover extrusion and are diagonally spaced with respect to each other. When installed, one valve covers one-half of the hopper, and the other valve the opposite half.
During outlet fabrication, a bulkhead sub-assembly is fitted into the bottom extrusion. This sub-assembly is used for mounting the inner end of respective valve shafts so the valves can be installed in their diagonally spaced configuration. The sub-assembly is force fitted into place. When installed, there are typically gaps and flat spots between the bottom cover extrusion and the sub-assembly. After installation, the sub-assembly is welded to the inside of the bottom cover. At that time, any gaps or flat spots are taken off. However, because of the size and geometry of the cover/bulkhead assembly, it is not always possible to eliminate all of the distortions between the two. Accordingly, gaps, for example, may remain.
Certain ladings carried in covered hopper cars are required to be essentially free of any contaminating material. The presence of contaminants in this material can it render it worthless. The presence of gaps in the outlet assembly provides locations where lading material can lodge during an unloading operation. If this material is dislodged during a subsequent unloading, the lading then being unloaded may be contaminated. It will be understood that not just particles from a prior lading, but dirt or other material may lodge in the gap and also act as a contaminant.
A second difficulty encountered during outlet fabrication is in aligning the outer end of the respective shafts. These outer ends are first installed on the end sheets of the assembly, and then connected to an adaptor. These adaptors are used for connecting the fluid discharge equipment to the outlet for unloading. The end sheets and adaptors are bolted together. Prior to doing this, the assembler must maneuver the shaft/end sheet assembly so to insure a proper alignment between the outlet valves and the sidewall of the outlet. He may, for example, do this using a feeler gauge. Once everything is aligned, he bolts the adaptor and end sheet together. It will be appreciated, however, that if there is even a small misalignment, additional gaps are formed in the outlet assembly which may add to the potential for contamination.